Methods

Included Modules

Instance Public methods

delete_all()

Deletes records in batches. Returns the total number of rows affected.

Person.in_batches.delete_all

See Relation#delete_all for details of how each batch is deleted.

📝 Source code 
# File activerecord/lib/active_record/relation/batches/batch_enumerator.rb, line 49
      def delete_all
        sum(&:delete_all)
      end
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destroy_all()

Destroys records in batches.

Person.where("age < 10").in_batches.destroy_all

See Relation#destroy_all for details of how each batch is destroyed.

📝 Source code 
# File activerecord/lib/active_record/relation/batches/batch_enumerator.rb, line 69
      def destroy_all
        each(&:destroy_all)
      end
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each()

Yields an ActiveRecord::Relation object for each batch of records.

Person.in_batches.each do |relation|
  relation.update_all(awesome: true)
end
📝 Source code 
# File activerecord/lib/active_record/relation/batches/batch_enumerator.rb, line 78
      def each
        enum = @relation.to_enum(:in_batches, of: @of, start: @start, finish: @finish, load: false)
        return enum.each { |relation| yield relation } if block_given?
        enum
      end
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each_record()

Looping through a collection of records from the database (using the all method, for example) is very inefficient since it will try to instantiate all the objects at once.

In that case, batch processing methods allow you to work with the records in batches, thereby greatly reducing memory consumption.

Person.in_batches.each_record do |person|
  person.do_awesome_stuff
end

Person.where("age > 21").in_batches(of: 10).each_record do |person|
  person.party_all_night!
end

If you do not provide a block to each_record, it will return an Enumerator for chaining with other methods:

Person.in_batches.each_record.with_index do |person, index|
  person.award_trophy(index + 1)
end
📝 Source code 
# File activerecord/lib/active_record/relation/batches/batch_enumerator.rb, line 36
      def each_record
        return to_enum(:each_record) unless block_given?

        @relation.to_enum(:in_batches, of: @of, start: @start, finish: @finish, load: true).each do |relation|
          relation.records.each { |record| yield record }
        end
      end
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update_all(updates)

Updates records in batches. Returns the total number of rows affected.

Person.in_batches.update_all("age = age + 1")

See Relation#update_all for details of how each batch is updated.

📝 Source code 
# File activerecord/lib/active_record/relation/batches/batch_enumerator.rb, line 58
      def update_all(updates)
        sum do |relation|
          relation.update_all(updates)
        end
      end
🔎 See on GitHub